MPG Increase?

Cowgirl

Cowgirl

Well-Known Member
I drive a little Cavalier that had been getting about 29 MPG over the summer, and dropped to 27ish over the winter. I just took a trip to NC last weekend, and I got 29 MPG on the tank of gas I got in MD. I filled up again in southern VA (maybe South Hill?). That tank got me all the way to Winston-Salem, and back to near the NC/VA line I think. I got 35 MPG on that tank! I just filled up this morning, so it was most of the trip back and back and forth to work this week, and it's back to 31 MPG. I realize that highway driving is best, but my "town" driving isn't even really town driving. :lol: The trip to work is about 25 miles, with no lights and only 1 stop sign. The rest of the time I'm cruising on 301. I just don't know why my normal MPG is 27-28 lately, but it gets up to 35. Is the gas better outside of MD?
 
aps45819

aps45819

24/7 Single Dad
Check the pressure in your tires. If you run them on the high side of the range listed on the sidewall, you 'll get better miliage.
Harder tires = less resistance to rolling = better mpg
 
Cowgirl

Cowgirl

Well-Known Member
aps45819 said:
Check the pressure in your tires. If you run them on the high side of the range listed on the sidewall, you 'll get better miliage.
Harder tires = less resistance to rolling = better mpg
Click to expand...

Ok, but I didn't add air to my tires on the trip. Do you think there could be a difference in the quality of gas?
 
Bonehead

Bonehead

Well-Known Member
I burn diesel in my car and I know there is a difference between winter and summer diesel. My mileage always drops during the winter. Don't know if there are different additives in the winter that may change you mileage.
 
GWguy

GWguy

*
Different areas may have different blends/additives depending on region and time of year. It's possible you got a batch that gave you better mileage.

I know at the peak of the gas pricing, fuel I got at both Sunoco and Sheetz (93 octane) was causing my truck to ping. It was not the same as we got before, and are getting now. I can run 89 octane with no pings now.
 
glhs837

glhs837

Power with Control
Tire pressure varies about 1psi per each 10 degrees of temp. Dont know that we've had that big a difference between us and SC to make a real difference, especially given that once you drive about 10 miles, your tires are heated up enough that the pressure in the tire is the same if outside temps are within 15-20 degrees of each other.

I suspect the gas. As noted, different areas get different blends, and some places get different blends based on the season.
 
glhs837

glhs837

Power with Control
nicole_M said:
:yeahthat: My tire pressure sensors come on when it's cold out. They go off after I've driven for 10 minutes or so.
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Your tires should be set to the specified pressure when cold, me, in October, I set them that way, then adjust again in spring. If your light is on before you drive, even after the light goes out, your still under inflated, which will affect your handling and mileage. The light is set to alert you to a dangerously low pressure, not manufacturer spec. My car, for instance recommends 32psi, but my low light doesn't come on until 28psi.
 
GWguy

GWguy

*
CG, do you normally get gas that contains alcohol? And did you happen to notice if the fuel you got out-of-state had alcohol blend? That could def account for the variance if yo got non-alcohol blended fuel.
 
Cowgirl

Cowgirl

Well-Known Member
GWguy said:
CG, do you normally get gas that contains alcohol? And did you happen to notice if the fuel you got out-of-state had alcohol blend? That could def account for the variance if yo got non-alcohol blended fuel.
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I didn't pay attention. :ohwell: Maybe that tank from South Hill didn't have it. :shrug:

I really don't think it was the tire pressure, because the temp difference wasn't that much from MD to NC.
 
N

nicole_M

New Member
glhs837 said:
Your tires should be set to the specified pressure when cold, me, in October, I set them that way, then adjust again in spring. If your light is on before you drive, even after the light goes out, your still under inflated, which will affect your handling and mileage. The light is set to alert you to a dangerously low pressure, not manufacturer spec. My car, for instance recommends 32psi, but my low light doesn't come on until 28psi.
Click to expand...

Jeez, I don't know much about that. My DH checks it for me all the time b/c the light comes on fairly often in cold temps and the pressure is always good.

I have 2 separate warnings, one for 'Tire Pressure Low' and one "WARNING: Tire Pressure Extremely Low" or something similar. I've had the 2nd one come on once and my tire WAS low, but anytime it's been the 1st warning, they've been fine.

My uncle has an Expedition as well and he has the same problem. I hate it b/c when the warning comes on I am expecting it to go off after a few miles. It's as if I don't know whether to take the warning seriously or not :lol: Though I always have someone check just incase.

Thanks for the info.
 
huntr1

huntr1

.
Cowgirl said:
I didn't pay attention. :ohwell: Maybe that tank from South Hill didn't have it. :shrug:

I really don't think it was the tire pressure, because the temp difference wasn't that much from MD to NC.
Click to expand...
Ethanol blended fuel cuts MPG by 10% I believe I read back when the ethanol craze started to take off.
 
glhs837

glhs837

Power with Control
Depends on the system ,and when he checks. If you drive even 3-4 miles, your pressure reading is going to be artificially high. Your tires heart up as you drive, and gain psi. From my house to work, about 7 miles, my tires go from 36-39/40psi. My car lets me see each tires pressure real time on my dash.

To be accurate, it needs to be checked before driving the car at all, or make an allowance of that effect. If the only time its going off is in the AM, before driving, its about %99 sure your tires are not at the right pressure cold.
 
John Z

John Z

if you will
I see a lot of pumps that say "contains up to 10% ethanol", so I assume that gives them the lattitude for each fillup to have 0% to 10% ethanol. So you'll never know how much energy per gallon you really have. Adding to that is "winter gas" often contains "oxegenates" and I have no idea what states/counties/etc have that, and when the cutover dates are (which might vary by location". I assume that St. Mary's doesn't have oxegenates because they don't have emissions testing. But I would guess those variables alone could account for 10% or so change in MPG.
 
Elle

Elle

Happy Camper!
Could it just be simple highway vs. city mileage? I know when we go on trip our MPG increased drastically b/c we aren't doing all the start and stopping – I mean like 5-7 MPG difference.
 
Cowgirl

Cowgirl

Well-Known Member
Elle said:
Could it just be simple highway vs. city mileage? I know when we go on trip our MPG increased drastically b/c we aren't doing all the start and stopping – I mean like 5-7 MPG difference.
Click to expand...

Possibly, but my "city" driving is very rural...not at all like St. Mary's.
 
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